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The Center for Materials Research

Welcome to the web sites of the Center for Materials Research

Welcome to the web sites of the Center for Materials Research!

The Center for Materials Research is an interdisciplinary university research center at JLU.
It is dedicated to the implementation of joint research projects, the support of the study courses in materials science and it promotes scientific qualification in materials research.

An overview of our scientific team is available under 
Team & Topics.

The center provides the participating research groups with central experimental resources in its
Method Platforms.

The ZfM coordinates the JLU research profile area ("area of potential") 
Material and Energy (focus: storage materials). 

Further information on our tasks can be found under
About us.

May

Picture of the Month - May 2025

Characterizing mesoscopic transport in single non-intentionally-doped GaN nanowire field-effect transistors

Semiconducting nanowires have gained much attention as they are promising building blocks for a vast number of nanoscaled electronic and optoelectronic devices. In particular, GaN nanowires are of high interest due to their direct band gap, high electron mobility and high break down fields outperforming the electrical properties of silicon counterparts. Beside their technological importance, GaN nanowires are also an interesting material system for studying mesoscopic transport, where the quantum mechanical properties of the electrons must be taken into account. In mesoscopic systems, such as nanowires, quantum interference effects can arise at low temperatures, if the characteristic dimensions are comparable to the so-called phase coherence length of the electron, i.e., the distance an electron wave can travel through the nanowire without loosing its phase due to inelastic scattering events. Typically, the interference effects in nanowires are studied by applying an external magnetic field, which changes the electron path and, thus, affects the interference effects. This results in so-called universal quantum fluctuations (UCF) of the resistance.

While Ge-doped GaN nanowires exhibit pronounced UCFs, no mesoscopic signatures are found for non-intentionally doped GaN nanowires when performing magnetic field dependent measurements. Instead, UCFs arise in single non-intentionally doped GaN nanowire field-effect transistor, when applying a gate-voltage as shown by Hergert et al.. The reason is that the electric field shifts the position of the Fermi-level inside the nanowire changing the effective impurity configuration. Thus, electric field dependent studies offer an alternative approach to characterize fundamental transport properties in low-dimensional systems.

For more details: H. Hergert, M.F. Zscherp, P. Klement, J. Schörmann, S. Chatterjee, P.J. Klar & M.T. Elm, Physica Status Solidi (a) 21, 2400040 (2024), https://doi.org/10.1002/pssa.202400040

This picture was submitted by Prof. Dr. Matthias Elm.

Further insights into the research activities of the ZfM groups can be found in the Gallery.

Portlet links engl.

Management of the Center

Study Programs in Materials' Science

 
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